diff --git a/tests/lean/run/mapTR.lean b/tests/lean/run/mapTR.lean
new file mode 100644
index 0000000000..bc6fac40f5
--- /dev/null
+++ b/tests/lean/run/mapTR.lean
@@ -0,0 +1 @@
+#eval (List.range 100000).map (.+1) |>.length